Facile fabrication of polyurethane/poly(methyl methacrylate) semi-interpenetrating polymer networks for enhanced mechanical and thermal properties

The primary objective of this research is to fabricate semi-interpenetrating polymer networks (semi-IPNs) via in-situ polymerization of methyl methacrylate (MMA) within a polyurethane (PU) framework. To produce polymethyl methacrylate (PMMA) from MMA in the PU matrix, solution polymerization was utilized in the following weight ratios: 30/70, 50/50, 70/30, and 90/10. The effective formation of semi-IPNs of PU/PMMA was confirmed by several techniques. Fourier transform infrared (FTIR) proves that no new chemical bonds formed between the semi-IPNs, and only physical interactions were present, and X-ray diffraction (XRD) techniques tell about the amorphous nature of these semi-IPNs. The field emission scanning electron microscope (FESEM) and atomic force microscope (AFM) were utilized to examine the morphology of PU/PMMA semi-IPNs. In contrast to alternative semi-IPNs, 70/30 and 90/10 PU/PMMA exhibit a uniform morphology devoid of phase separation. Furthermore, the significant thermal stability and transitions of these semi-IPNs were assessed using a thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Additionally, the mechanical analysis indicates that among the different percentages of PU/PMMA, 70/30 PU/PMMA exhibits the highest tensile strength of approximately 50.5 MPa. The observed enhancement in mechanical strength can be attributed to interpenetrating networks (IPNs) formed between the constituents. The synthesized PU/PMMA semi-IPNs have potential in various fields, including medical devices, automotive components, sports, and other advanced applications.